16
5.
INSPECTION
5.1.
PRELIMINARY CHECKS
-
THE
DELIVERY
AND
OUTLET
HYDRAULIC
CONNECTIONS must be completed. Check the pressure
seal of the various circuits and the free passage they
afford to the carrying fluid
-
THE
INTAKE
AND
DELIVERY
AIR-MOVING
CONNECTIONS must be completed. Check the tightness of
the lines against air leaks in both the main sections and
the various branches leading to the utilisation points
- THE EXTERNAL AIR INTAKES AND OUTLETS must
present entirely free passages. If the Units remain on site
for some time prior to inspection, make sure that the
passages have not become obstructed by foreign matter
and that the flow control locks are not in the fully or
partly closed position. TCF fits standard on outdoor
installations special "RAIN-SHIELDS" complete with leaf-
collection net with a mesh size of 10 mm x 1 mm. It is
however advisable to check that these air intakes are free
of obstructions.
Similarly you must make sure that there are no air locks
in the closed position in the AIR DISTRIBUTION CIRCUITS
and that any safety systems installed, such as lire or
smoke gates, are not activated and blocking the air
passage
- THE CARRIER FLUIDS such as hot or superheated water;
steam, cooled water glycol mixtures or cooling gases must
be available in the actual conditions (temperature and
pressure) considered at the design stage
- THE POWER AND CONTROL BOARDS must be supplied
with the normal operating voltage
- OUTSIDE WEATHER CONDITIONS, DIFFERENT FROM
THOSE CONSIDERED ATTHE DESIGN STAGE, must be
assessed and made allowance for so as to ensure that the
inspection is reliable.
5.2.
INSPECTION PROCEDURES
5.2.1. Power board
Inspect the motor control board and check that the motor
protection devices are sized for the maximum amperage
corresponding to the rated value.
lf the protection devices are sized for an amperage in
excess of the rated value, you must make sure that the
working range is sufficient.
5.2.2. Flowrate check
- Using an oil or water column pressure gauge or an
analogue and/or digital gauge, check the FLOW
RESISTANCE in the various filtration sections and
consequently their fouling factor. The TREATED AIR
FLOW can be determined with a good degree of precision
on the basis of the filters' operating curve and the
working life considered at the design stage.
To make this check you must first take pressure readings
at the PRESSURE POINTS in front of and behind each
filtration section (on request, TCF can provide the
relevant attachments during manufacture)
- Compare the flow rate value obtained as described
above with the value obtained from the following
formula:
Q = 3600xSxV where:
Q = flow rate in m“/h
V = air velocity in Ws
S = passage area in m
2
The velocity value "V" can be measured with hot-wire or
revolving-vane anemometers.
You must deduct from the front area of the grilles or
inlets the area lost through the presence of the conveying
fins in order to consider just the NET PASSAGE SECTION.
The area occupied by the fins can be obtained from the
technical specifications and is, on average, approximately
15% of the total area.
In order to take VELOCITY MB\SUREMENTS with the
HOFWIRE ANEMOMETER, holes of sufficient diameter to
allow the introduction of the telescopic probe must be
made in the ducts.
You should select straight duct sections at least 2.5
equivalent diameters in length or as far away as possible
from obstructions or points of probable turbulence. In
order to obtain reliable flow rate measurements, a
PERFORATED GRID must be made in the duct according
to the "point sampling" method shown in fig. 33.
